1. Field of the Invention
The present invention relates to a fluorescent light detection device configured to irradiate a test object with an excitation light and detect a fluorescent light produced by the test object.
2. Description of the Related Art
A growing number of fluorescent light detection devices have been used in the field of life science. A fluorescent light detection device is easy-to-use and has high detection sensitivity. A fluorescent light detection device may sometimes be used in combination with an amplification step for efficient quantitative detection of nucleic acid such as DNA labeled by a fluorescent chemical substance.
For example, patent document 1 discloses a fluorescent light analysis optical module provided with an excitation light source configured to emit an excitation light having a main wavelength λ1, a fluorescent light analysis optical multiplexer/demultiplexer configured to multiplex or demultiplex a fluorescent light having a main wavelength λ2 produced by a sample irradiated with the excitation light via a probe; a detector configured to receive the fluorescent light transmitted through the fluorescent light analysis multiplexer/demultiplexer, a first light guide connecting the excitation light source and the optical multiplexer/demultiplexer, a second light guide connecting the probe to the optical multiplexer/demultiplexer, and a third light guide connecting the detector and the optical multiplexer/demultiplexer.    [patent document 1] JP2005-30830
The optical multiplexer/demultiplexer used in the invention described in cited document 1 is comprised of a first rod lens, a filter provided on the surface of the first rod lens, and a second rod lens secured to the filter. The optical multiplexer/demultiplexer is built by assembling these components serially and integrally. An optical multiplexer/demultiplexer of such a configuration tends to require a lot of effort and skill for positioning of the components in order to achieve highly efficient optical coupling using a rod lens and a filter. Therefore, the teachings disclosed in patent document 1 leaves room for improvement in terms of the cost.